Hawaiian Monk Seal

Sealed in the Past:
Save the Hawaiian Monk Seal
By: Ben Bray

Hawaiian Monk Seal

Organism Description & Ecology
The Hawaiian monk seal, scientifically known as Neomonachus schauinslandi, is one of the rarest marine mammals in the entire world. This particular member of the Phoncidae is also a part of the earless seal subspecies. Weighing in between 375-450 pounds and measuring around 7 feet long, these silvery-grey mammals are somewhat like a living fossil because they are one of two remaining monk seal species left on the planet. The Hawaiian monk seal can live to be between 25 and 30 years of age. These monk seals are also one of two mammals endemic to the Hawaiian Islands, joining the Hawaiian Hoary Bat. Just like every other carnivore in the ocean, the Hawaiian monk seal feeds on fish, cephalopods (squid, octopus, etc.) or crustaceans. Monk seals are seen during the day resting on beaches and you can tell which of them are not yet mature because newborns and young ones are black or a darker grey and even light patches of red and green can be seen from attached algae.

Geographic & Population Changes

Graph showing the declining number of monk seals in the
Northwestern Hawaiian Islands

Hawaiian monk seals live in the warm subtropical waters around the main Hawaiian islands and the northwestern islands. Monk seals spend about two-thirds of their time at sea and can be seen using sandy beaches, corals, and volcanic rock to breed as well as haul-out. The Hawaiian monk seal's entire range is only within U.S. waters and the majority of the monk seals can be seen living in six main breeding sub-populations within the Northwestern Islands. These particular places are: Kure Atoll, Midway Islands, Pearl and Hermes Reef, Lisianski Island, Laysan Island, and the French Frigate Shoals. However, these are not the only breeding spots for the Hawaiian monk seals, as they have been observed in smaller sub-populations on Necker Island, Nihoa Island, Gardner Pinnacles, and Maro Reef. As you can see, monk seals set up camp wherever they can be protected and lay out in the sun with some easy access to the water. When it comes to the population of this earless seal, they have declined from an already slim 1,520 total individuals in 1983 to 1,209 individuals in 2011, with only 632 of that total in 2011 being mature males or females. That is roughly half of the monk seal population being immature or newborns.

Listing Date & Listing Type
The Hawaiian monk seal was listed as endangered on August 22, 2007. The reasons for this
listing include human interactions, food limitation, and shark predation. The Recovery Plan for saving the monk seals is now finalized and has been approved by the Regional Director.

Cause of Listing & Main Threats
Human Interaction: Almost everyone who is on a beach and sees a seal is going to want to get a closer look or even a closer picture. This is a large impact that humans have on monk seals and how they are threatened in the wild. Usually on these beaches there will be a mother and her pup resting or it could even be a newborn on its way to the water for the first time. A family on the beach is not the only way that humans affect the Hawaiian monk seals. Becoming bycatch in a fisherman's net, for example, is another way monk seals are directly affected by humans and our actions. Hawaiian monk seals can swim in the ocean and become entrapped nets even if they were just abandoned there.

Hawaiian Monk Seal

Food Limitation: Limited options for prey appears to be a main factor in the continuous decline of the Hawaiian monk seal population. The inability to have foraging success has directly affected body condition, growth, age of maturation--and in particular--survival rates of juvenile seals. Now unable to receive the proper nutrients, these monk seals are unhealthy and struggle to fight parasitic infections and recover from injuries. If the younger monk seals are unable to survive, this means that the few young, female Hawaiian monk seals who do survive are only reproducing a few offspring. Through this process, the total population will decline rapidly with each generation of offspring that are born in the Hawaiian islands.

Shark Predation: At French Frigate Shoals in the Northwestern Hawaiian Islands, a major cause in the decreasing survival rate of recently born pups is because of the Galapagos shark. It is estimated that around 30% of all pups born at French Frigate Shoals are killed as a result of shark predation. Galapagos sharks are found throughout the Hawaiian islands, however, this severity of shark predation is extremely rare in areas other than FFS. There are reasons to believe that a fairly small group of sharks are penetrating the shallow spots near the shore in order to target the monk seal pups. Shark predation around FFS has caused the population of seals to decrease by over 75% from 1989-2010. Some courses of action that the Hawaiian Monk Seal Research Program has taken include the translocation of newborn monk seal pups. This has allowed them to get to a safe place where they can mature and get into the water without becoming prey to the nearby Galapagos sharks.

Recovery Plan

Hawaiian Monk Seal injured by shark bite

The main goal of the recovery plan is to assure the long-term survival of the Hawaiian monk seal in the wild, which will ultimately lead to the reclassification to threatened status and, in the end, removal from the List of Endangered and Threatened Wildlife. To do so, the first course of action must be to improve the mortality rate of young pups and female monk seals. The biggest goal of the entire plan is to ensure that the young and female monk seals are able to survive their trip from the beach back to the water and vice versa. Whether the disturbance be caused by humans or sharks, the primary action is to make sure they can mature fully and healthily in order to be able to reproduce. The population of Hawaiian monk seals, as stated in the recovery plan, will be reclassified as "threatened" if: the aggregate numbers exceed 2,900 total monk seals in the Northwestern Hawaiian islands, at least 5 of the 6 main sub-populations in the Northwestern Hawaiian islands are above 100 individuals and the Main Hawaiian island population is above 500, and also the population growth rate in both the Northwestern islands and the Main island cannot be negative.

What Can We Do?
To the normal beachgoer enjoying his or her time in Hawaii: don't get any closer to that seal you see about a half a mile down the shore. Who knows if that Hawaiian monk seal could be distressed or nursing her own newborn pup. To go along with not disturbing the monk seal on the beach, humans like you and I can clean up after ourselves and not litter because any type of trash we leave in the environment can find its way to making a significant impact in the world.

Hawaiian monk seal Recovery Plan


References
"Hawaiian Monk Seal (Neomonachus Schauinslandi)." NOAA Fisheries. N.p., 21 Aug. 2015. Web. 3 Dec. 2015. <http://www.fisheries.noaa.gov/pr/species/mammals/seals/hawaiian-monk-seal.html>.

Littnan, C., Harting, A. & Baker, J. 2015.  Neomonachus schauinslandi. The IUCN Red List of Threatened Species 2015: e.T13654A45227978. http://dx.doi.org/10.2305/IUCN.UK.2015-2.RLTS.T13654A45227978.en. Downloaded on 03 December 2015.

"Threats To Hawaiian Monk Seal Survival." NOAA Fisheries. N.p., n.d. Web. 3 Dec. 2015. <http://www.pifsc.noaa.gov/hawaiian_monk_seal/threats_to_survival.php>.